Rotary stages and platforms have been used to provide a wider angle of view to, for example, imaging devices including cameras for some time. Cameras or other technical devices are installed as part of a payload on a rotary stage or platform. It is generally desirable to identify the angle of rotation of which the technical device is oriented. Efforts to identify the angular orientation require the use of complex encoders in combination with expensive, high accuracy rotary drives. It has been customary to signal the rotary drive in intended angular orientation to rotate the stage to the angular orientation without performing any remedial measurement to determine the angular orientation of the stage or platform. To achieve some degree of accuracy, the drive typically includes a stepper motor that is particularly costly when working in combination with an encoder to direct the motor to the desired orientation. Achieving a high degree of accuracy has still proven elusive, particularly at a reasonable cost. To achieve a high degree of accuracy, the prior art rotary drives are known to dither or oscillate around a target angular orientation while attempting to establish desired accuracy. Even high cost rotary drives can only achieve a degree of accuracy that makes it difficult to use the payload for high precision operations such as, for example, template laser projection, photographic measurement, and inspection systems performed on large objects, such as, for example, an airplane fuselage that requires a wide angle of view not achievable by a stationary system.
In addition, rotary platforms or stages have not included provisions to determine tilt of a platform or stage from away from a vertical axis or axis of rotation. Therefore, the platforms or stages must be secured in highly accurate horizontal orientation. Alternatively, tilt is simply ignored reducing accuracy of the imaging device located on the platform or stage.
Alternatively, to perform these functions on a large object, the payload is moved a long distance from the object further resulting in reduction in accuracy. A low cost system to overcome these problems has not yet been found. Therefore, it would be desirable to provide a rotary stage or platform capable of working in unison with the highly technical payload such as, for example, a laser projector, the photogrammetric measurement system, or an inspection system that is low cost, and simple to maintain that is capable of providing a high degree of accuracy.